[dpdk-dev] [PATCH v2 4/4] eal: cache last directory permissions checked

[Bruce Richardson <bruce.richardson@intel.com>]

When loading a directory of drivers, we check the same hierarchy multiple
times. If we just cache the last directory checked, this avoids repeated
checks of the same path, since all drivers in that path have been added to
the list consecutively.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
---
V2: Fix checkpatch issue for unnecessary else.
---
 lib/librte_eal/common/eal_common_options.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/librte_eal/common/eal_common_options.c b/lib/librte_eal/common/eal_common_options.c
index 6978e6744..e6b2a195f 100644
--- a/lib/librte_eal/common/eal_common_options.c
+++ b/lib/librte_eal/common/eal_common_options.c
@@ -388,11 +388,17 @@ verify_perms(const char *dirpath)
 
 	/* if not root, check down one level first */
 	if (strcmp(dirpath, "/") != 0) {
+		static __thread char last_dir_checked[PATH_MAX];
 		char copy[PATH_MAX];
+		const char *dir;
 
 		strlcpy(copy, dirpath, PATH_MAX);
-		if (verify_perms(dirname(copy)) != 0)
-			return -1;
+		dir = dirname(copy);
+		if (strncmp(dir, last_dir_checked, PATH_MAX) != 0) {
+			if (verify_perms(dir) != 0)
+				return -1;
+			strlcpy(last_dir_checked, dir, PATH_MAX);
+		}
 	}
 
 	/* call stat to check for permissions and ensure not world writable */
-- 
2.25.1